Our original intent with the Mouse Core was to create a core that was rather different than other mouse cores. Our overarching goal was to use the Mouse Core to generate new transgenic and gene-targeted mouse lines that would allow us to test, as a group, fundamental problems in inner-ear biology. We intended therefore for the Mouse Core to have experfise in construct design and generafion, mouse husbandry, and genotyping. The reviewers of the first renewal submission easily picked up on the undeniable fact that we were far less successful than we had anficipated in making new mouse lines. Our original intent was to seed the construct-generation process by generating mouse lines that were more closely related to the interests of the Core PI, but that nevertheless tapped into topics of general interest to the OHRC group, such as mechanotransduction. However, the Mouse Core bogged down with construct generation and in obtaining germline transmission with its constructs. We are now at a position where we can begin to share the two generated mouse lines (TRPV5 and TRPV6 knock-ins) amongst the group, but we would have preferred to be here a few years ago. Moreover, the Mouse Core Scienfist, Jim Smart, who was capable of running all facets of the core, left for a more stable posifion, one with a long-term guarantee of employment. We had been lucky to get him at the salary we paid him, as he was quite experienced;we picked him straight out of graduate school, and were able to give him sufficient compensafion for the position to look attractive. That was not a long-term solufion for this position, however. This experience did point out that hiring someone with experience in making mouse lines was not easily done with the available P30 budget. In the meanfime, however, we had hired a Mouse Core Technician, Michael Bateschell, who demonstrated outstanding skill in the service-oriented aspects of the core. Combining the need to retain Bateschell and the plan to expand the core to included in utero electroporation, it became abundantly clear that we would not be able to hire someone for the core with sufficient molecular-genetics experience to be able to continue with the construct-generation service. The negative review of this core after its first renewal submission just reinforced this view.